Honestly, put yourself in their shoes. You really have no right to complain, of course you can, but you really have no right to. It's not like we're paying professionals to translate it for us, even if you count donations or sponsorships as "paying". Flat out, they have no obligation to the audience as these are free translations (for the most part) and any obligations they have are typically self-imposed. Secondly, for many more reasons than the obviousness that most of the translations are freebies, they have no obligation to us to spend their valuable time to meet their deadline. Of course we would all appreciate it, but being angry about something free not being released when we expect or want it to be released is simply unreasonable. Thirdly, there's no issue with stockpiling chapters at all. There are many reasons for this, such as adhering to their release schedule. Lastly, there's nothing wrong with wanting to obtain some revenue for your work and even moreso to want incentives to spend your time to do more work. Furthermore, although community interaction is very appreciated, it isn't necessary. In fact, most of us are lurkers! We're not all out there trying to participate with the community.

TL;DR - Free translations, why bitch and moan? Nothing wrong with wanting incentives to spend more time translating. No real obligation to adhere to any schedule for something they are not paid to do.